Wafer handling robot with radial gas curtain and/or interior volume control

ABSTRACT

Systems and techniques for reducing or eliminating particulate contamination from wafer handling robots configured for vertical translation are disclosed. In one such technique, a collar may be provided having an aperture through it through which the turret of a wafer handling robot may be extended or retracted. The collar may have one or more radial gas passages. Gas directed at the turret from the radial passage(s) may turn downward when it strikes the turret and may act to prevent or discourage gas from within the base of the wafer handling robot from escaping through the aperture. In another technique, a bellows may be affixed to the bottom of the turret and to the bottom of the base such that the volume of the base occupied by the turret and the bellows remains generally fixed regardless of the degree to which the turret is extended from the base.

A PCT Request Form is filed concurrently with this specification as partof the present application. Each application that the presentapplication claims benefit of or priority to as identified in theconcurrently filed PCT Request Form is incorporated by reference hereinin its entirety and for all purposes.

BACKGROUND

Semiconductor processing tools often make use of an equipment front-endmodule (EFEM), which is a large chamber or vestibule that is part of asemiconductor processing tool and which provides, generally on one side,load ports for receiving front-opening unified pods (FOUPs) used totransport wafers in bulk, e.g., 25 at a time, between semiconductorprocessing tools. EFEMs may also generally have, usually on a sideopposite the load ports, one or more load locks or other interfaces forintroducing wafers into a transfer chamber or processing chamber. Awafer handling robot is typically located within the EFEM in order totransfer wafers between the load ports and the load locks, as well aspotentially other stations in the EFEM, e.g., wafer aligners.

Wafer handling robots used in EFEMs often include the capability to movewafers both horizontally, via articulated arms that have arm links thatare each configured to rotate relative to the arm links they areattached to, and vertically, e.g., via a linear translation mechanismthat raises or lowers the entire robot arm assembly.

Presented herein are improved wafer handling robot configurations thatare particularly well-suited for use in certain types of EFEMs, e.g.,such as those that may have a corrosive environment inside, e.g., anenvironment with elevated moisture levels or having one or more gasespresent such as chlorine, fluorine, or other corrosive substances.

SUMMARY

Details of one or more implementations of the subject matter describedin this specification are set forth in the accompanying drawings and thedescription below. Other features, aspects, and advantages will becomeapparent from the description, the drawings, and the claims.

The present inventors conceived of at least two different mechanismsthat may be used either in isolation or in tandem to provide an improvedwafer handling robot. Both mechanisms reduce the likelihood ofparticulate contamination resulting from vertical (z-axis) movement ofthe wafer handling robot.

Wafer handling robots with z-axis capability typically include a base,which may be fixed with respect to the chamber or structure thatsupports them (such as an EFEM; such structures may simply be referredto herein as chambers, although this is to be understood to be inclusiveof EFEMs as well), a turret that is mounted to the base in a manner thatallows the turret to be moved vertically relative to the base, and oneor more robot arms that are supported by the turret and actuated bymotors located in the turret. The turret is typically largely containedwithin the base when the wafer handling robot is at its lowest verticalposition and may rise up out of the base through an opening in the basewhen elevated to a raised position. The present inventors determinedthat vertical movement of the turret relative to the base was a sourceof particulate contamination since, with each lowering or raising of theturret, air (or whatever atmosphere is present in the chamber) would beforced out of or drawn into the base due to the displacement of theturret within the base. For example, for a turret that is 8" in diameterand has a vertical travel of 18", the turret may displace over half acubic foot of volume as it travels.

Such displacement may cause gas that is located within the base to beexpelled into the ambient environment surrounding the wafers in thechamber or similar structure when the wafer handling robot is actuatedto a lower the robot arm, which may cause particulates that originatefrom equipment within the base to be expelled into the chamber, where itmay come into contact with and contaminate wafers that may be in thechamber. Such displacement may also cause air from within the chamber tobe drawn into the base of the wafer handling robot when the waferhandling robot is actuated so as to raise the robot arm, which maypresent issues in chambers that have corrosive gases present. Suchcorrosive gases may damage components internal to the base, e.g.,bearings, motors, electrical cables, etc., which may affect theperformance or operability of the wafer handling robot. Such corrosionmay also, it was recognized, result in further particulate generation,which may increase the chances of a wafer being subjected to particulatecontamination due to movement of the wafer handling robot.

The present inventors conceived of two particulate mitigationtechnologies that may be used in wafer handling robots such as thosedescribed above to mitigate or eliminate particulate contamination thatis attributable to turret displacement of such wafer handling robots.

The first technology is a collar or other structure that provides aradial gas curtain that extends completely around the turret at alocation near the top of the base. The radial gas curtain may deliver athin, radial stream of air (or other gas, such as nitrogen) towards theturret across a relatively small gap. This gas curtain, after it bridgesthe gap, strikes the side of the turret and turns so as to flow ingenerally vertical directions; some of this air flows into the base ofthe wafer handling robot and the rest of the air flows into the chamber.The portion of air that flows into the base will tend to push against orcounter whatever flow of air may be trying to flow out of the base atthe location of the gas curtain, thereby causing whatever particulatesthat may be entrained in such air to remain within the base. The portionof air that flows into the base may also tend to increase the internalpressure within the base (if the base has exhaust vents to allow suchgas to escape that are sized small enough to allow a positive pressuredifferential between the base and the ambient environment to develop).The resulting positive pressure in the base, relative to the chamber,may prevent corrosive elements from entering the base at locations otherthan the location of the gas curtain. The portion of the air that flowsfrom the collar or other structure and into the chamber will tend topush against or counter whatever flow of air may be trying to flow intothe base at the location of the gas curtain, thereby causing whatevercorrosive elements that may be entrained in such air to remain withinthe chamber. It will be understood that while frequent reference is madeherein to “air,” other gases may be used in place of air, e.g.,nitrogen, as discussed earlier.

The second technology is a bellows unit that may be affixed to thebottom end of the turret on one end and to the base on the other end.Thus, the bellows unit may expand into the interior volume of the basewhen the turret is raised and may compress when the turret is lowered.The bellows may act to cause the free volume within the base to remaingenerally constant regardless of the vertical position of the turretrelative to the base. As a result, there may be little or no grossdisplacement of air from the base due to the vertical movement of theturret relative to the base. The bellows may also act to preventpotentially corrosive air from the ambient environment of the chamberfrom being drawn into the base from the bottom.

While either technology may reduce the likelihood or severity ofparticulate contamination on its own, using both technologies may have asynergistic effect that may allow for the particulate generation rate ofthe wafer handling robot vertical movement system within the chamber tobe reduced to effectively nothing, e.g., <10 particles in a 72 minutewindow.

In some implementations, an apparatus may be provided that includes oneor more robot arms, a turret supporting the one or more robot arms, alinear translation mechanism supporting the turret, and a basesupporting the linear translation mechanism. In such an apparatus, thelinear translation mechanism may be configured to translate the turret,as well as the one or more robot arms, along a first axis relative tothe base, the base may include an aperture sized to allow at least afirst portion of the turret to pass therethrough when the turret istranslated along the first axis, the aperture may have one or moreradial gas passages extending around substantially all of the aperture,the one or more radial gas passages may be fixed in size, a first gapmay exist between an interior edge of the aperture and the first portionof the turret, and the first gap may extend around the outer perimeterof the first portion of the turret.

In some implementations of the apparatus, the first gap between thefirst portion of the turret and the interior edge of the aperture may befree of any intervening structure around substantially all of theturret.

In some implementations of the apparatus, the one or more radial gaspassages may have a minimum width in a direction parallel to the firstaxis that is less than 1 mm.

In some implementations of the apparatus, the one or more radial gaspassages may have a minimum width in a direction parallel to the firstaxis that is less than 0.5 mm.

In some implementations of the apparatus, the one or more radial gaspassages may have a minimum width in a direction parallel to the firstaxis that is less than or equal to 0.25 mm.

In some implementations of the apparatus, one or more radial gaspassages may be at least partially defined by one or more first surfacesand one or more second surfaces, and the one or more first surfaces mayface towards the one or more second surfaces and may be separated fromthe one or more second surfaces by a second gap.

In some implementations of the apparatus, the one or more first surfacesand the one or more second surfaces may be perpendicular to the firstaxis.

In some implementations of the apparatus, each of the one or more firstsurfaces may define a first cross-sectional radial profile with respectto a second axis that is parallel to the first axis and centered on theaperture, each of the one or more second surfaces may define a secondcross-sectional radial profile with respect to the second axis, thecross-sectional radial profiles may include the one or more firstcross-sectional radial profiles and the one or more secondcross-sectional radial profiles may each be in a corresponding planethat is coincident with and parallel to the second axis, each firstcross-sectional radial profile may define an average first linear radialprofile that is within ±30° of perpendicular to the second axis, andeach second cross-sectional radial profile may define an average secondlinear radial profile that is within ±30° of perpendicular to the secondaxis.

In some implementations of the apparatus, the apparatus may furtherinclude one or more plenum volumes, one or more gas inlets, and one ormore flow control components configured to regulate flow of gas to theone or more gas inlets. In such implementations, each gas inlet may befluidically connected with one of the one or more plenum volumes, eachof the one or more plenum volumes may be fluidically connected with atleast one of the one or more gas inlets, each of the one or more gasinlets may be fluidically interposed between one of the one or moreplenum volumes and one of the one or more flow control components, andeach of the one or more plenum volumes may be fluidically interposedbetween one of the one or more gas inlets and the one or more radial gaspassages.

In some implementations of the apparatus, the apparatus may furtherinclude one or more gas sources, and the one or more flow controlcomponents may be fluidically connected with the one or more gas sourcesand configured to cause gas from the one or more gas sources to beprovided to the one or more plenum volumes at a rate of between 25 and150 standard liters per minute. In such implementations, the one or moreradial gas passages may be sized such that the gas from the one or moreplenum volumes flows from the one or more radial gas passages with avelocity of at least 5 m/s.

In some implementations of the apparatus, the first portion of theturret may have a first nominally circular cross-section and theaperture may have a corresponding second nominally circularcross-section with a diameter larger than the diameter of the firstnominally circular cross-section.

In some implementations of the apparatus, the one or more radial gaspassages may include only a single gas passage that is in the form of aradial slit that extends around the entire aperture without anydisruptions in continuity.

In some implementations of the apparatus, the first gap may be between0.5 mm and 5 mm around the turret.

In some implementations of the apparatus, the apparatus may furtherinclude a bellows. A first end of the bellows may be fixed relative toan end of the turret located within the base, a second end of thebellows opposite the first end may be fixed relative to a surface of thebase on an opposite side of the base from the aperture, the bellows mayexpand responsive to translation of the turret away from the surface ofthe base, and the bellows may contract responsive to translation of theturret towards the surface of the base.

In some implementations of the apparatus, the bellows may have a firstaverage enclosed cross-sectional area when viewed along the first axis,the outermost surface or surfaces of the first portion of the turret maydefine a second average cross-sectional area when viewed along the firstaxis, and the first average enclosed cross-sectional area may besubstantially equal to the second average cross-sectional area.

In some implementations of the apparatus, the first portion of theturret may be nominally circular and may have a first nominal diameter,the bellows may have a plurality of pleats, each pleat may have an innerdiameter and an outer diameter, and the average of the inner diametersand outer diameters of the pleats may be substantially equal to thefirst nominal diameter.

In some implementations of the apparatus, the base may have one or morevents in the surface of the base and within a region encircled by thebellows when viewed along the first axis.

In some implementations, an apparatus may be provided which includes oneor more robot arms, a turret supporting the one or more robot arms, alinear translation mechanism supporting the turret, a bellows, and abase supporting the linear translation mechanism. In suchimplementations, the linear translation mechanism may be configured totranslate the turret, as well as the one or more robot arms, along afirst axis relative to the base, the base may include an aperture sizedto allow at least a first portion of the turret to pass therethroughwhen the turret is translated along the first axis, a first end of thebellows may be fixed relative to a first end of the turret locatedwithin the base, a second end of the bellows opposite the first end ofthe bellows may be fixed relative to a first surface of the base on anopposite side of the base from the aperture, the bellows may expandresponsive to translation of the turret away from the surface of thebase, and the bellows may contract responsive to translation of theturret towards the surface of the base.

In some implementations of the apparatus, there may be no bellowsconnecting the turret with a second surface of the base opposite thefirst surface of the base.

In some implementations of the apparatus, the bellows may have a firstaverage enclosed cross-sectional area when viewed along the first axis,the outermost surface or surfaces of the first portion of the turret maydefine a second average cross-sectional area when viewed along the firstaxis, and the first average enclosed cross-sectional area may besubstantially equal to the second average cross-sectional area.

In some implementations of the apparatus, the first portion of theturret may be nominally circular and may have a first nominal diameter,the bellows may have a plurality of pleats, each pleat may have an innerdiameter and an outer diameter, and the average of the inner diametersand outer diameters of the pleats may be substantially equal to thefirst nominal diameter.

In some implementations of the apparatus, the base may have one or morevents in the surface of the base and within a region encircled by thebellows when viewed along the first axis.

In some implementations of the apparatus, the aperture may have one ormore radial gas passages extending around substantially all of theaperture, the one or more radial gas passages may be fixed in size, afirst gap may exist between an interior edge of the aperture and thefirst portion of the turret, and the first gap may extend around theouter perimeter of the first portion of the turret.

In some implementations of the apparatus, the first gap between thefirst portion of the turret and the interior edge of the aperture may befree of any intervening structure.

In some implementations of the apparatus, the one or more radial gaspassages may have a minimum width in a direction parallel to the firstaxis that is less than 1 mm.

In some implementations of the apparatus, the one or more radial gaspassages may have a minimum width in a direction parallel to the firstaxis that is less than 0.5 mm.

In some implementations of the apparatus, the one or more radial gaspassages may have a minimum width in a direction parallel to the firstaxis that is less than or equal to 0.25 mm.

In some implementations of the apparatus, the one or more radial gaspassages may be at least partially defined by one or more first surfacesand one or more second surfaces, and the one or more first surfaces mayface towards the one or more second surfaces and may be separated fromthe one or more second surfaces by a second gap.

In some implementations of the apparatus, the one or more first surfacesand the one or more second surfaces may be perpendicular to the firstaxis.

In some implementations of the apparatus, each of the one or more firstsurfaces may define a first cross-sectional radial profile with respectto a second axis that is parallel to the first axis and centered on theaperture, each of the one or more second surfaces may define a secondcross-sectional radial profile with respect to the second axis, thecross-sectional radial profiles including the one or more firstcross-sectional radial profiles and the one or more secondcross-sectional radial profiles may each be in a corresponding planethat is coincident with and parallel to the second axis, each firstcross-sectional radial profile may define an average first linear radialprofile that is within ±30° of perpendicular to the second axis, andeach second cross-sectional radial profile may define an average secondlinear radial profile that is within ±30° of perpendicular to the secondaxis.

In some implementations of the apparatus, the apparatus may furtherinclude one or more plenum volumes, one or more gas inlets, and one ormore flow control components configured to regulate flow of gas to theone or more gas inlets. In such implementations, each gas inlet may befluidically connected with one of the one or more plenum volumes, eachof the one or more plenum volumes may be fluidically connected with atleast one of the one or more gas inlets, each of the one or more gasinlets may be fluidically interposed between one of the one or moreplenum volumes and one of the one or more flow control components, andeach of the one or more plenum volumes may be fluidically interposedbetween one of the one or more gas inlets and the one or more radial gaspassages.

In some implementations of the apparatus, the apparatus may include oneor more gas sources. In such implementations, the one or more flowcontrol components may be fluidically connected with the one or more gassources and may be configured to cause gas from the one or more gassources to be provided to the one or more plenum volumes at a rate ofbetween 25 and 150 standard liters per minute and the one or more radialgas passages may be sized such that the gas from the one or more plenumvolumes flows from the one or more radial gas passages with a velocityof at least 5 m/s.

In some implementations of the apparatus, the first portion of theturret may have a first nominally circular cross-section and theaperture may have a corresponding second nominally circularcross-section with a diameter larger than the diameter of the firstnominally circular cross-section.

In some implementations of the apparatus, the one or more radial gaspassages may include only a single gas passage that is in the form of aradial slit that extends around the entire aperture without anydisruptions in continuity.

In some implementations of the apparatus, the first gap may be between0.5 mm and 5 mm around the turret.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a diagram of an example semiconductor processing tool.

FIG. 2 is a diagram of an example EFEM with an example wafer handlingrobot in a first configuration.

FIG. 3 is a diagram of the example EFEM of FIG. 2 with the example waferhandling robot in a second configuration.

FIG. 4 is a diagram of the example EFEM of FIG. 2 with the example waferhandling robot in a third configuration.

FIG. 5 is a cross-sectional diagram of a portion of an example gascurtain system.

FIG. 6 is a cross-sectional diagram of a portion of another example gascurtain system.

FIG. 7 is a cross-section diagram of another example gas curtain system.

FIG. 8 is a top view section diagram of an example gas curtain system.

FIG. 9 is a top view section diagram of another example gas curtainsystem.

FIG. 10 is a top view section diagram of another example gas curtainsystem.

DETAILED DESCRIPTION

As discussed above, wafer handling robots used in EFEMs or other typesof semiconductor processing tool chambers may utilize systems such asthose briefly described above to reduce particulate production by thewafer handling robot and reduce the likelihood of, for example, theinternal components of the wafer handling robot from being exposed tocorrosive gases (if the wafer handling robot is used in such anenvironment).

FIG. 1 depicts a diagram of an example semiconductor processing tool. InFIG. 1 , a semiconductor processing tool 100 is shown that includes anEFEM 110 with a wafer handling robot 114 located within. The EFEM 110may be connected with one or more load ports 106 that may allow wafershoused within a FOUP 108 to be transferred into the EFEM 110 by thewafer handling robot 114. The EFEM 110 may also be connected with atransfer chamber 102 (or other chamber, such as a processing chamber) byone or more loadlocks 104. The EFEM 110 may also be equipped with a fanunit 112 that may cause the air within the EFEM to be forced downwardinto a vent system in the floor of the EFEM 110; in otherimplementation, the vent system may simply be connected with a negativepressure source, e.g., an exhaust system with a blower unit, to draw airdownward through the EFEM 110 (in yet other implementations, the EFEMmay not have a vent system at all).

FIG. 2 is a diagram of an example EFEM with an example wafer handlingrobot in a first configuration. In FIG. 2 , an EFEM 210 is shown; theEFEM 210 in this example is not shown attached to other components,e.g., load ports, load locks, etc., to avoid undue clutter and allow thediscussion to focus on the wafer handling robot 214. The wafer handlingrobot 214 may include, for example, a base 230 that has within it alinear translation mechanism 242 that is configured to raise or lower aturret 224. The linear translation mechanism 242 in this exampleincludes a ball screw 244 that may pass through a ball screw nut 246that is affixed to the turret 224 and is supported on one end by abearing support 248 and on the other end by a motor 250. When the motor250 is actuated to turn the ball screw 244, the ball screw 244 causesthe ball screw nut 246 to raise and lower, thereby causing the turret224 to extend or retract through an aperture 252 along a directionparallel to a first axis 238. The base 230 may have a housing thatgenerally encloses and protects the hardware within the base 230; thishousing may, however, have various openings or leak paths through itthat may allow for gas to flow between the interior and exterior of thehousing (discussed later below).

The turret 224 may support one or more robot arms that may contain, forexample, an upper link 218, a lower link 220, and an end effector 222,which may be actuated by various drive motors and other systems locatedwithin the turret (or elsewhere).

As discussed earlier, the wafer handling robot may include either orboth of two technologies described herein that may mitigate particlegeneration by the wafer handling robot and/or help protect the waferhandling robot from potential harmful exposure to corrosive ambientenvironments.

The first technology discussed in more detail below is the inclusion ofa radial gas curtain that may be provided by a collar 232 that definesthe aperture 252. The collar 232 may include one or more radial gaspassages 234 that are fluidically connected with a plenum volume 236within the collar 232. Gas may be flowed into the plenum volume 236through one or more gas inlets (not shown) and may then flow towards theturret 224 in a radially inward manner from the one or more radial gaspassages 234 at a relatively high velocity, e.g., 5 m/s, 10 m/s, 15 m/s,20 m/s, 25 m/s, or higher. The one or more radial gas passages 234 maybe sized to be relatively thin, e.g., having a height less than or equalto 1 mm, 0.75 mm, 0.5 mm, or 0.25 mm, so as to achieve the desired gasvelocity with a reduced amount of volumetric gas flow, e.g., avolumetric gas flow rate of between 25 and 150 standard liters perminute (SLM) or 50 to 100 SLM. A first gap 240 may exist between theturret 224 and the collar 232 to allow a first portion 226 of the turret224 to translate through the aperture 252 without contacting the collar232. This first gap 240 may be kept to a value less than or equal to (orbetween) 5 mm, 4 mm, 3 mm, 2 mm, 1 mm, or 0.5 mm. In this example, theturret 224 is generally cylindrical and has a first nominal diameter228, and the aperture 252 is a circular aperture with a nominal diameterequal to twice the first gap 240 plus the first nominal diameter 228. Itwill be understood that other implementations may feature a turret 224with a different nominal cross-sectional shape, e.g., square, hexagonal,etc., and that the aperture 252 in the collar 232 may be similarlyshaped so that the first gap 240 remains generally constant, e.g., ±10%or ±20%, around the perimeter of the first portion 226 of the turret224.

As noted above and described in more detail later below, a gas such asclean dry air, nitrogen, or other gas that may be compatible with theenvironment within the EFEM and/or with the wafer handling robotinternal components may be flowed through the plenum volume 236, out theone or more radial gas passages 234, and radially inwards towards theouter surface of the turret 224, which may then cause the gas flow toturn so as to flow both upwards and downwards along the outer surface ofthe turret 224. The portion of the gas that flows downward into the base230 may serve to push against whatever gases may be attempting to flowout of the base through the first gap 240, thereby resisting the flow ofgases, and whatever particulates may be entrained therein, from withinthe base 230 and through the aperture 252. The base 230 may also haveone or more exhaust fans 265 that may be positioned along a surface ofthe base 230, e.g., the bottom surface 264, of the base 230, and whichmay be controlled to evacuate gas from within the base so as to relievepressure from within the base 230. The speed of the fan(s) may becontrolled such that the volumetric flow rate of the gas through thefans is nominally equal to the volumetric flow rate of the gas throughthe aperture 252 and into the base 230, e.g., approximately one half thevolumetric flow rate of the gas out of the collar 232. This may allowwhatever pressure accumulates within the base 230 due to the gas flowfrom the collar 232 to bleed off, thereby permitting the gas flow fromthe collar 232 to continue to counter the flow of gas from within thebase 230. The gas that is flowed out of the base 230 by the fans may, insome implementations, be drawn downwards by the downdraft in an EFEMthat is equipped with a floor-located exhaust system. In otherimplementations, the fans 265 may be omitted and replaced by one or morevents or exhaust ports that may be provided to allow gas that isintroduced into the base 230 by the collar 232 to vent out of the base230 and into the ambient environment of the EFEM 210 or other chamberwithin which the base 230 is located. In such cases, the vents orexhaust port(s) may be sized such that, during normal operation (i.e.,with the EFEM 210 or other chamber at a nominal ambient pressurecondition used during wafer transfer operations and with the collar 232or other structure providing a radial gas curtain at a nominal flowrate), an internal pressure is maintained in the base 230 that is atleast a few Pascals above that of the ambient pressure within the EFEM210, thereby preventing or reducing the possibility of corrosive gasesin the ambient environment of the EFEM 210 of entering the base 230.

The second technology that may be included in a wafer handling robot,either by itself or in combination with the radial gas curtain discussedabove, is the use of a bellows 254 that spans between the bottom of theturret 224 and the bottom surface 264. The bellows 254, which may bemade of a flexible material, such as an elastomeric material,elastomer-impregnated textile, or thin metal, may include a first end260 that is affixed to the bottom surface or surfaces of the turret 224and a second end 262 that is affixed to the bottom surface 264 of thebase 230. The bottom surface 264 of the base 230 may have a vent (orvents) 258 that may allow gas within the bellows 254 to escape when thebellows 254 is compressed, e.g., when the turret 224 is moved from araised position to a lowered position.

In some implementations, the bellows 254 may have a plurality of pleats256 that each have an inner diameter 266 and an outer diameter 268. Theinner diameter 266 and the outer diameter 268 of the pleats 256 of thebellows 254 may be selected so as to produce an average diameter that isgenerally equal to, e.g., within ±10% or ±20%, the first nominaldiameter 228 of the first portion 226 of the turret 224. By selectingthe inner diameter 266 and the outer diameter 268 in this manner, theturret 224 and the bellows 254 together may occupy a volume within thebase 230 that remains nominally constant in size regardless of how faror little the turret 224 is extended from the base 230. As a result,when the turret 224 translates into or out of the base 230, the volumeof gas that is displaced within the base 230 (which does not include thevolume of air that is within the base 230 but “walled off” from theinterior volume of the base 230 by the bellows 254) may be negligible.Thus, using a bellows 254 as shown in FIG. 2 prevents the reciprocatingaction of the turret 2 from causing gas from within the base to beforcibly expelled through the aperture 252 (or at least drasticallyreduces the amount of such gas that may be expelled). FIG. 3 is adiagram of the example EFEM of FIG. 2 with the example wafer handlingrobot in a second configuration, e.g., partially extended, and FIG. 4 isa diagram of the example EFEM of FIG. 2 with the example wafer handlingrobot in a third configuration, e.g., fully retracted. As can be seen ineach configuration, the internal volume 231 of the base 230 staysapproximately the same regardless of how much the turret 224 is extendedor retracted. Accordingly, use of a bellows in the manner shown in FIGS.2 through 4 may allow the turret 224 of the wafer handling robot 214 toextend or retract with very little in the way of air (or gas)displacement within the base 230. This may drastically reduce thepossibility of particulates that are entrained within such gas frombeing forcibly expelled from the base 230 by such reciprocating actionof the turret.

It will also be appreciated that the bellows discussed above may be usedin conjunction with turrets that are not nominally cylindrical in shape.In such implementations, the inner and outer diameters of the bellowspleats may be selected so as to define an average cross-sectional area(for example, based on the area within a circle having a diameter thatis the average of the inner and outer diameters of the bellows pleats)that is generally equal to the cross-sectional area within the outermostsurfaces of the first portion of the turret and within a planeperpendicular to the first axis 238 (or, if a non-circular bellows isused, the average cross-sectional area of the bellows, including thearea within the bellows, may be generally equal to the cross-sectionalarea within the outermost surfaces of the first portion of the turret).

As discussed earlier, the bellows discussed above may be used with orwithout the radial gas curtain feature discussed previously (and viceversa). The radial gas curtain feature may be configured in a number ofdifferent ways, as is discussed in more detail below.

FIG. 5 is a cross-sectional diagram of a portion of an example gascurtain system. As can be seen in FIG. 5 , a collar 532 may have aplenum volume 536 that is fed air by one or more gas inlets 574. Theplenum volume 236 may be configured to distribute gas from the one ormore gas inlets 574 to one or more radial gas passages 534. The one ormore radial gas passages 534 may be directed radially inward, e.g.,across a first gap 540 and towards turret 524, so as to direct gas,e.g., air, from the plenum volume 536 towards the turret 524. In theimplementation shown in FIG. 5 , the one or more radial gas passages 534takes the form of a single circumferential radial slit that extends allthe way around the turret 524. The radial gas passage 534 in this caseis provided by a first surface 580 and a second surface 582, which mayface each other and be separated by a second gap 584. The first surface580 may be defined by a first cross-sectional radial profile 586, whichis a line in this example, and may be represented by an average firstlinear radial profile 590. The second surface 582, similarly, may bedefined by a second cross-sectional radial profile 588, which is also aline in this example, and may be represented by an average second linearradial profile 592.

While FIG. 5 shows a linear radial slit, i.e., one in which the averagefirst linear radial profile 590 and the average second linear radialprofile 592 are parallel to each other and perpendicular to a first axis538, as an example radial gas passage, other configurations of radialgas passage may be used as well, including, for example, radial gaspassages having curved or sloped first and second surfaces.

FIG. 6 is a cross-sectional diagram of a portion of another example gascurtain system. The gas curtain system of FIG. 6 is similar to that ofFIG. 5 , and callouts with the same last two digits in FIG. 6 as in FIG.5 refer to analogous structures; the reader is referred to the previousdiscussion in FIG. 5 for discussion of these structures. The gas curtainsystem of FIG. 6 differs from that of FIG. 5 in that the radial gaspassage 634 has a different cross-sectional profile. For example, theradial gas passage 634 is defined by a first surface 680 and a secondsurface 682. The first surface 680 may have a curved firstcross-sectional radial profile 686 which defines an average first linearradial profile 690 and a curved second cross-sectional radial profile688 that defines an average second linear radial profile 692. In somesuch implementations, the average first linear radial profile 690 andthe average second linear radial profile 692 may each be within ±10°,±20°, or ±30° of an axis that is perpendicular to the first axis 638. Insome further such implementations, the average first linear profile 690and the average second linear profile 292 may, for example, be anglednon-symmetrically relative to the axis that is perpendicular to thefirst axis 638. For example, the average first linear profile 690 andthe average second linear profile 292 may both be angled slightlydownward, towards the base, thereby causing the flow of the radialcurtain gas to be biased more towards the base 230 than into the EFEM210 after it strikes the turret 224. In another example, the averagefirst linear profile 690 and the average second linear profile 292 mayboth be angled slightly upward, away from the base, thereby causing theflow of the radial curtain gas to be biased more into the EFEM 210 thaninto the base 230 after it strikes the turret 224. This may allow fortuning of the amount of gas that is allocated for preventing air fromwithin the base 230 from entering the EFEM 230 via the aperture 252versus for preventing gas from within the EFEM 230 from entering thebase 230 via the aperture 252.

As discussed earlier, the gas that is directed out of the one or moreradial gas passages of one of the collars discussed herein may bedirected towards the turret of a wafer handling robot. FIG. 7 is across-section diagram of an example gas curtain system showing such gasflow. As can be seen in FIG. 7 , a collar 732 is shown which has aplenum volume 736 that receives gas from gas inlets 774 (as shown by theair flow arrows) and distributes the gas to a radial gas passage 734.The gas, after being expelled from the radial gas passage 734, isdirected radially inward, across a first gap 740, such that it strikesthe side of the turret 724. The gas flow then splits into two generaldirections—upwards, back into the EFEM, and downwards, into the base.

It will be understood that the collars discussed above, and the radialgas passage(s) that they include, may be provided in a number offormats. In some implementations, the collar may be integrated into thehousing of the base or another component rather than be a separatecomponent. Some implementations of the gas curtain systems discussedherein may feature radial gas passages of varying geometries. Some ofthese various implementations are discussed below.

FIG. 8 is a top view section diagram of an example gas curtain system.In FIG. 8 , a collar 832 is shown that includes a plenum volume 836 thatis provided gas through gas inlets 874. A turret 824 extends through anaperture in the collar 832 and is separated from the collar 832 by afirst gap 840. Gas from the plenum volume 836 may be flowed across thefirst gap 840 through a radial gas passage 834 that is, like with someof the earlier collars discussed herein, a single circumferential radialslit. Such a radial gas passage 834 may provide evenly distributed gasflow around the circumference of the turret 824.

FIG. 9 is a top view section diagram of another example gas curtainsystem. The gas curtain system of FIG. 9 is similar to that of FIG. 8 ,and callouts with the same last two digits in FIG. 9 as in FIG. 8 referto analogous structures; the reader is referred to the previousdiscussion in FIG. 8 for discussion of these structures. The gas curtainsystem of FIG. 9 , in contrast to that of FIG. 8 , features four radialgas passages 934, each spanning approximately 90° of arc and separatedfrom the adjoining radial gas passages 934 by a small radial wall (notindicated, but visible at the 12 o’clock, 3 o’clock, 6 o’clock, and 9o’clock positions. Such an arrangement may provide a substantiallycontinuous radial gas curtain around the circumference of the turret 924since the small radial walls may provide only minimal interruption ofthe gas flow. The small radial walls may, however, provide a usefulmechanism for helping maintain a constant height for the radial gaspassages 934.

FIG. 10 is a top view section diagram of another example gas curtainsystem. The gas curtain system of FIG. 10 is similar to that of FIG. 8 ,and callouts with the same last two digits in FIG. 10 as in FIG. 8 referto analogous structures; the reader is referred to the previousdiscussion in FIG. 8 for discussion of these structures. In FIG. 10 ,there are a large number, e.g., 72, of radial gas passages 1034, witheach radial gas passage 1034 being a radially extending hole or channel.Such individual radial gas passages may be arranged so that they arearranged in a closely-packed arrangement extending around the outerperiphery of the turret 1024 so as to supply a generally continuouscurtain of gas around the periphery of the turret 1024 via theindividual holes or channels.

It will be appreciated that the radial gas curtain systems discussedabove offer consistent and unvarying performance since the one or moreradial gas passages that are used in such systems direct gas directly atthe turret and fixed in size, i.e., the second gaps of such radial gaspassages cannot vary over time (aside from potential thermal expansioneffects). This is in contrast to floating seal systems in which a sealthat encircles a shaft is caused to “float” in space, cushions by a thinlayer of gas that is flowed along its outer, upper, and lowersurfaces—in such systems, the gaps through which the gas flows maychange in size due to floating movement of the seal, leading to changesin flow conductance of the gaps and accompanying fluctuations in gasflow rate for such gaps. Additionally, the use of a floating sealintroduces a further potential source of particular generation, as theseal itself can potentially contact other components and may therebygenerate particulate matter that is then ejected from the seal regionand potentially into the EFEM. Such radial gas curtain systems alsooffer advantages over systems in which an annular plenum around a shaftis provided pressurized gas through, for example, a small number of gasports, e.g., 2 or 4 or 8 gas ports. In such systems, the gas that flowsthrough smaller annular outlet zones above and below the annular plenumand along the shaft may see circumferential flow fluctuations due topressure differentials within the annular plenum due to the low numberof gas ports as compared with the gas curtain systems discussed herein,which direct a generally continuous radial gas curtain radially inward,there by creating a more uniform gas flow distribution.

Wafer handling robots having one or both technologies discussed abovemay be part of a larger semiconductor processing tool, as discussedearlier, which may be controlled by one or more controllers.

The controller may be part of a system that may include theabove-described examples, and may be operatively connected with variousvalves, mass flow controllers, pumps, etc. so as to be able to receiveinformation from and/or control such equipment. Such systems can includesemiconductor processing equipment, including a processing tool ortools, chamber or chambers, a platform or platforms for processing,and/or specific processing components (a wafer pedestal, a gas flowsystem, etc.). These systems may be integrated with electronics forcontrolling their operation before, during, and after processing of asemiconductor wafer or substrate. The electronics may be referred to asthe “controller,” which may control various components or subparts ofthe system or systems. The controller, depending on the processingrequirements and/or the type of system, may be programmed to control anyof the processes disclosed herein, including the delivery of variousgases, temperature settings (e.g., heating and/or cooling), pressuresettings, vacuum settings, power settings, flow rate settings, fluiddelivery settings, and positional and operation settings.

Broadly speaking, the controller may be defined as electronics havingvarious integrated circuits, logic, memory, and/or software that receiveinstructions, issue instructions, control operation, enable cleaningoperations, enable endpoint measurements, and the like. The integratedcircuits may include chips in the form of firmware that store programinstructions, digital signal processors (DSPs), chips defined asapplication specific integrated circuits (ASICs), and/or one or moremicroprocessors, or microcontrollers that execute program instructions(e.g., software). Program instructions may be instructions communicatedto the controller in the form of various individual settings (or programfiles), defining operational parameters for carrying out a particularprocess on or for a semiconductor wafer or to a system. The operationalparameters may, in some implementations, be part of a recipe defined byprocess engineers to accomplish one or more processing steps during thefabrication of one or more layers, materials, metals, oxides, silicon,silicon dioxide, surfaces, circuits, and/or dies of a wafer.

The controller, in some implementations, may be a part of or coupled toa computer that is integrated with, coupled to the system, otherwisenetworked to the system, or a combination thereof. For example, thecontroller may be in the “cloud” or all or a part of a fab host computersystem, which can allow for remote access of the wafer processing. Thecomputer may enable remote access to the system to monitor currentprogress of fabrication operations, examine a history of pastfabrication operations, examine trends or performance metrics from aplurality of fabrication operations, to change parameters of currentprocessing, to set processing steps to follow a current processing, orto start a new process. In some examples, a remote computer (e.g. aserver) can provide process recipes to a system over a network, whichmay include a local network or the Internet. The remote computer mayinclude a user interface that enables entry or programming of parametersand/or settings, which are then communicated to the system from theremote computer. In some examples, the controller receives instructionsin the form of data, which specify parameters for each of the processingsteps to be performed during one or more operations. It should beunderstood that the parameters may be specific to the type of process tobe performed and the type of tool that the controller is configured tointerface with or control. Thus as described above, the controller maybe distributed, such as by comprising one or more discrete controllersthat are networked together and working towards a common purpose, suchas the processes and controls described herein. An example of adistributed controller for such purposes would be one or more integratedcircuits on a chamber in communication with one or more integratedcircuits located remotely (such as at the platform level or as part of aremote computer) that combine to control a process on the chamber.

Without limitation, example systems may include a plasma etch chamber ormodule, a deposition chamber or module, a spin-rinse chamber or module,a metal plating chamber or module, a clean chamber or module, a beveledge etch chamber or module, a physical vapor deposition (PVD) chamberor module, a chemical vapor deposition (CVD) chamber or module, anatomic layer deposition (ALD) chamber or module, an atomic layer etch(ALE) chamber or module, an ion implantation chamber or module, a trackchamber or module, and any other semiconductor processing systems thatmay be associated or used in the fabrication and/or manufacturing ofsemiconductor wafers.

As noted above, depending on the process step or steps to be performedby the tool, the controller might communicate with one or more of othertool circuits or modules, other tool components, cluster tools, othertool interfaces, adjacent tools, neighboring tools, tools locatedthroughout a factory, a main computer, another controller, or tools usedin material transport that bring containers of wafers to and from toollocations and/or load ports in a semiconductor manufacturing factory.

For the purposes of this disclosure, the term “fluidically connected” isused with respect to volumes, plenums, holes, etc., that may beconnected with one another in order to form a fluidic connection,similar to how the term “electrically connected” is used with respect tocomponents that are connected together to form an electric connection.The term “fluidically interposed,” if used, may be used to refer to acomponent, volume, plenum, or hole that is fluidically connected with atleast two other components, volumes, plenums, or holes such that fluidflowing from one of those other components, volumes, plenums, or holesto the other or another of those components, volumes, plenums, or holeswould first flow through the “fluidically interposed” component beforereaching that other or another of those components, volumes, plenums, orholes. For example, if a pump is fluidically interposed between areservoir and an outlet, fluid that flowed from the reservoir to theoutlet would first flow through the pump before reaching the outlet.

It is to be understood that the phrases “for each <item> of the one ormore <items>,” “each <item> of the one or more <items>,” or the like, ifused herein, are inclusive of both a single-item group and multiple-itemgroups, i.e., the phrase “for... each” is used in the sense that it isused in programming languages to refer to each item of whateverpopulation of items is referenced. For example, if the population ofitems referenced is a single item, then “each” would refer to only thatsingle item (despite the fact that dictionary definitions of “each”frequently define the term to refer to “every one of two or morethings”) and would not imply that there must be at least two of thoseitems. Similarly, the term “set” or “subset” should not be viewed, initself, as necessarily encompassing a plurality of items—it will beunderstood that a set or a subset can encompass only one member ormultiple members (unless the context indicates otherwise).

The use, if any, of ordinal indicators, e.g., (a), (b), (c)... or thelike, in this disclosure and claims is to be understood as not conveyingany particular order or sequence, except to the extent that such anorder or sequence is explicitly indicated. For example, if there arethree steps labeled (i), (ii), and (iii), it is to be understood thatthese steps may be performed in any order (or even concurrently, if nototherwise contraindicated) unless indicated otherwise. For example, ifstep (ii) involves the handling of an element that is created in step(i), then step (ii) may be viewed as happening at some point after step(i). Similarly, if step (i) involves the handling of an element that iscreated in step (ii), the reverse is to be understood.

Terms such as “about,” “approximately,” “substantially,” “nominal,” orthe like, when used in reference to quantities or similar quantifiableproperties, are to be understood to be inclusive of values within ±10%of the values or relationship specified (as well as inclusive of theactual values or relationship specified), unless otherwise indicated.

It should be appreciated that all combinations of the foregoing concepts(provided such concepts are not mutually inconsistent) are contemplatedas being part of the inventive subject matter disclosed herein. Inparticular, all combinations of claimed subject matter appearing at theend of this disclosure are contemplated as being part of the inventivesubject matter disclosed herein. It should also be appreciated thatterminology explicitly employed herein that also may appear in anydisclosure incorporated by reference should be accorded a meaning mostconsistent with the particular concepts disclosed herein.

It is to be further understood that the above disclosure, while focusingon a particular example implementation or implementations, is notlimited to only the discussed example, but may also apply to similarvariants and mechanisms as well, and such similar variants andmechanisms are also considered to be within the scope of thisdisclosure. It is to be additionally understood that the abovedisclosure is intended to encompass at least the following numberedimplementations.

Implementation 1: An apparatus comprising: one or more robot arms; aturret supporting the one or more robot arms; a linear translationmechanism supporting the turret; and a base supporting the lineartranslation mechanism, wherein: the linear translation mechanism isconfigured to translate the turret, as well as the one or more robotarms, along a first axis relative to the base, the base includes anaperture sized to allow at least a first portion of the turret to passtherethrough when the turret is translated along the first axis, theaperture has one or more radial gas passages extending aroundsubstantially all of the aperture, the one or more radial gas passagesare fixed in size, a first gap exists between an interior edge of theaperture and the first portion of the turret, and the first gap extendsaround the outer perimeter of the first portion of the turret.

Implementation 2: The apparatus of implementation 1, wherein the firstgap between the first portion of the turret and the interior edge of theaperture is free of any intervening structure around substantially allof the turret.

Implementation 3: The apparatus of implementation 1, wherein the one ormore radial gas passages have a minimum width in a direction parallel tothe first axis that is less than 1 mm.

Implementation 4: The apparatus of implementation 1, wherein the one ormore radial gas passages have a minimum width in a direction parallel tothe first axis that is less than 0.5 mm.

Implementation 5: The apparatus of implementation 1, wherein the one ormore radial gas passages have a minimum width in a direction parallel tothe first axis that is less than or equal to 0.25 mm.

Implementation 6: The apparatus of implementation 1, wherein: one ormore radial gas passages are at least partially defined by one or morefirst surfaces and one or more second surfaces, and the one or morefirst surfaces face towards the one or more second surfaces and areseparated from the one or more second surfaces by a second gap.

Implementation 7: The apparatus of implementation 6, wherein the one ormore first surfaces and the one or more second surfaces areperpendicular to the first axis.

Implementation 8: The apparatus of implementation 6, wherein: each ofthe one or more first surfaces defines a first cross-sectional radialprofile with respect to a second axis that is parallel to the first axisand centered on the aperture, each of the one or more second surfacesdefines a second cross-sectional radial profile with respect to thesecond axis, the cross-sectional radial profiles including the one ormore first cross-sectional radial profiles and the one or more secondcross-sectional radial profiles are each in a corresponding plane thatis coincident with and parallel to the second axis, each firstcross-sectional radial profile defines an average first linear radialprofile that is within ±30° of perpendicular to the second axis, andeach second cross-sectional radial profile defines an average secondlinear radial profile that is within ±30° of perpendicular to the secondaxis.

Implementation 9: The apparatus of implementation 1, further comprising:one or more plenum volumes; one or more gas inlets; and one or more flowcontrol components configured to regulate flow of gas to the one or moregas inlets, wherein: each gas inlet is fluidically connected with one ofthe one or more plenum volumes, each of the one or more plenum volumesis fluidically connected with at least one of the one or more gasinlets, each of the one or more gas inlets is fluidically interposedbetween one of the one or more plenum volumes and one of the one or moreflow control components, and each of the one or more plenum volumes isfluidically interposed between one of the one or more gas inlets and theone or more radial gas passages.

Implementation 10: The apparatus of implementation 9, further comprisingone or more gas sources, wherein: the one or more flow controlcomponents are fluidically connected with the one or more gas sourcesand are configured to cause gas from the one or more gas sources to beprovided to the one or more plenum volumes at a rate of between 25 and150 standard liters per minute and the one or more radial gas passagesare sized such that the gas from the one or more plenum volumes flowsfrom the one or more radial gas passages with a velocity of at least 5m/s.

Implementation 11: The apparatus of implementation 1, wherein the firstportion of the turret has a first nominally circular cross-section andthe aperture has a corresponding second nominally circular cross-sectionwith a diameter larger than the diameter of the first nominally circularcross-section.

Implementation 12: The apparatus of implementation 1, wherein the one ormore radial gas passages includes only a single gas passage that is inthe form of a radial slit that extends around the entire aperturewithout any disruptions in continuity.

Implementation 13: The apparatus of implementation 1, wherein the firstgap is between 0.5 mm and 5 mm around the turret.

Implementation 14: The apparatus of implementation 1, further comprisinga bellows, wherein: a first end of the bellows is fixed relative to anend of the turret located within the base, a second end of the bellowsopposite the first end is fixed relative to a surface of the base on anopposite side of the base from the aperture, the bellows expandsresponsive to translation of the turret away from the surface of thebase, and the bellows contracts responsive to translation of the turrettowards the surface of the base.

Implementation 15: The apparatus of implementation 14, wherein: thebellows has a first average enclosed cross-sectional area when viewedalong the first axis, the outermost surface or surfaces of the firstportion of the turret define a second average cross-sectional area whenviewed along the first axis, and the first average enclosedcross-sectional area is substantially equal to the second averagecross-sectional area.

Implementation 16: The apparatus of implementation 14, wherein: thefirst portion of the turret is nominally circular and has a firstnominal diameter, the bellows has a plurality of pleats, each pleat hasan inner diameter and an outer diameter, and the average of the innerdiameters and outer diameters of the pleats is substantially equal tothe first nominal diameter.

Implementation 17: The apparatus of implementation 14, wherein the basehas one or more vents in the surface of the base and within a regionencircled by the bellows when viewed along the first axis.

Implementation 18: An apparatus comprising: one or more robot arms; aturret supporting the one or more robot arms; a linear translationmechanism supporting the turret; a bellows; and a base supporting thelinear translation mechanism, wherein: the linear translation mechanismis configured to translate the turret, as well as the one or more robotarms, along a first axis relative to the base, the base includes anaperture sized to allow at least a first portion of the turret to passtherethrough when the turret is translated along the first axis, a firstend of the bellows is fixed relative to a first end of the turretlocated within the base, a second end of the bellows opposite the firstend of the bellows is fixed relative to a first surface of the base onan opposite side of the base from the aperture, the bellows expandsresponsive to translation of the turret away from the surface of thebase, and the bellows contracts responsive to translation of the turrettowards the surface of the base.

Implementation 19: The apparatus of implementation 18, wherein there areno bellows connecting the turret with a second surface of the baseopposite the first surface of the base.

Implementation 20: The apparatus of implementation 18, wherein: thebellows has a first average enclosed cross-sectional area when viewedalong the first axis, the outermost surface or surfaces of the firstportion of the turret define a second average cross-sectional area whenviewed along the first axis, and the first average enclosedcross-sectional area is substantially equal to the second averagecross-sectional area.

Implementation 21: The apparatus of implementation 18, wherein: thefirst portion of the turret is nominally circular and has a firstnominal diameter, the bellows has a plurality of pleats, each pleat hasan inner diameter and an outer diameter, and the average of the innerdiameters and outer diameters of the pleats is substantially equal tothe first nominal diameter.

Implementation 22: The apparatus of implementation 18, wherein the basehas one or more vents in the surface of the base and within a regionencircled by the bellows when viewed along the first axis.

Implementation 23: The apparatus of implementation 18, wherein: theaperture has one or more radial gas passages extending aroundsubstantially all of the aperture, the one or more radial gas passagesare fixed in size, a first gap exists between an interior edge of theaperture and the first portion of the turret, and the first gap extendsaround the outer perimeter of the first portion of the turret.

Implementation 24: The apparatus of implementation 23, wherein the firstgap between the first portion of the turret and the interior edge of theaperture is free of any intervening structure.

Implementation 25: The apparatus of implementation 23, wherein the oneor more radial gas passages have a minimum width in a direction parallelto the first axis that is less than 1 mm.

Implementation 26: The apparatus of implementation 23, wherein the oneor more radial gas passages have a minimum width in a direction parallelto the first axis that is less than 0.5 mm.

Implementation 27: The apparatus of implementation 23, wherein the oneor more radial gas passages have a minimum width in a direction parallelto the first axis that is less than or equal to 0.25 mm.

Implementation 28: The apparatus of implementation 23, wherein: the oneor more radial gas passages are at least partially defined by one ormore first surfaces and one or more second surfaces, and the one or morefirst surfaces face towards the one or more second surfaces and areseparated from the one or more second surfaces by a second gap.

Implementation 29: The apparatus of implementation 28, wherein the oneor more first surfaces and the one or more second surfaces areperpendicular to the first axis.

Implementation 30: The apparatus of implementation 28, wherein: each ofthe one or more first surfaces defines a first cross-sectional radialprofile with respect to a second axis that is parallel to the first axisand centered on the aperture, each of the one or more second surfacesdefines a second cross-sectional radial profile with respect to thesecond axis, the cross-sectional radial profiles including the one ormore first cross-sectional radial profiles and the one or more secondcross-sectional radial profiles are each in a corresponding plane thatis coincident with and parallel to the second axis, each firstcross-sectional radial profile defines an average first linear radialprofile that is within ±30° of perpendicular to the second axis, andeach second cross-sectional radial profile defines an average secondlinear radial profile that is within ±30° of perpendicular to the secondaxis.

Implementation 31: The apparatus of implementation 23, furthercomprising: one or more plenum volumes; one or more gas inlets; and oneor more flow control components configured to regulate flow of gas tothe one or more gas inlets, wherein: each gas inlet is fluidicallyconnected with one of the one or more plenum volumes, each of the one ormore plenum volumes is fluidically connected with at least one of theone or more gas inlets, each of the one or more gas inlets isfluidically interposed between one of the one or more plenum volumes andone of the one or more flow control components, and each of the one ormore plenum volumes is fluidically interposed between one of the one ormore gas inlets and the one or more radial gas passages.

Implementation 32: The apparatus of implementation 31, furthercomprising one or more gas sources, wherein: the one or more flowcontrol components are fluidically connected with the one or more gassources and are configured to cause gas from the one or more gas sourcesto be provided to the one or more plenum volumes at a rate of between 25and 150 standard liters per minute and the one or more radial gaspassages are sized such that the gas from the one or more plenum volumesflows from the one or more radial gas passages with a velocity of atleast 5 m/s.

Implementation 33: The apparatus of implementation 23, wherein the firstportion of the turret has a first nominally circular cross-section andthe aperture has a corresponding second nominally circular cross-sectionwith a diameter larger than the diameter of the first nominally circularcross-section.

Implementation 34: The apparatus of implementation 23, wherein the oneor more radial gas passages includes only a single gas passage that isin the form of a radial slit that extends around the entire aperturewithout any disruptions in continuity.

Implementation 35: The apparatus of implementation 23, wherein the firstgap is between 0.5 mm and 5 mm around the turret.

What is claimed is:
 1. An apparatus comprising: one or more robot arms;a turret supporting the one or more robot arms; a linear translationmechanism supporting the turret; and a base supporting the lineartranslation mechanism, wherein: the linear translation mechanism isconfigured to translate the turret, as well as the one or more robotarms, along a first axis relative to the base, the base includes anaperture sized to allow at least a first portion of the turret to passtherethrough when the turret is translated along the first axis, theaperture has one or more radial gas passages extending aroundsubstantially all of the aperture, the one or more radial gas passagesare fixed in size, a first gap exists between an interior edge of theaperture and the first portion of the turret, and the first gap extendsaround the outer perimeter of the first portion of the turret.
 2. Theapparatus of claim 1, wherein the first gap between the first portion ofthe turret and the interior edge of the aperture is free of anyintervening structure around substantially all of the turret.
 3. Theapparatus of claim 1, wherein the one or more radial gas passages have aminimum width in a direction parallel to the first axis that is lessthan 1 mm.
 4. The apparatus of claim 1, wherein the one or more radialgas passages have a minimum width in a direction parallel to the firstaxis that is less than 0.5 mm.
 5. The apparatus of claim 1, wherein theone or more radial gas passages have a minimum width in a directionparallel to the first axis that is less than or equal to 0.25 mm.
 6. Theapparatus of claim 1, wherein: one or more radial gas passages are atleast partially defined by one or more first surfaces and one or moresecond surfaces, and the one or more first surfaces face towards the oneor more second surfaces and are separated from the one or more secondsurfaces by a second gap.
 7. The apparatus of claim 6, wherein the oneor more first surfaces and the one or more second surfaces areperpendicular to the first axis.
 8. The apparatus of claim 6, wherein:each of the one or more first surfaces defines a first cross-sectionalradial profile with respect to a second axis that is parallel to thefirst axis and centered on the aperture, each of the one or more secondsurfaces defines a second cross-sectional radial profile with respect tothe second axis, the cross-sectional radial profiles including the oneor more first cross-sectional radial profiles and the one or more secondcross-sectional radial profiles are each in a corresponding plane thatis coincident with and parallel to the second axis, each firstcross-sectional radial profile defines an average first linear radialprofile that is within ±30° of perpendicular to the second axis, andeach second cross-sectional radial profile defines an average secondlinear radial profile that is within ±30° of perpendicular to the secondaxis.
 9. The apparatus of claim 1, further comprising: one or moreplenum volumes; one or more gas inlets; and one or more flow controlcomponents configured to regulate flow of gas to the one or more gasinlets, wherein: each gas inlet is fluidically connected with one of theone or more plenum volumes, each of the one or more plenum volumes isfluidically connected with at least one of the one or more gas inlets,each of the one or more gas inlets is fluidically interposed between oneof the one or more plenum volumes and one of the one or more flowcontrol components, and each of the one or more plenum volumes isfluidically interposed between one of the one or more gas inlets and theone or more radial gas passages.
 10. The apparatus of claim 9, furthercomprising one or more gas sources, wherein: the one or more flowcontrol components are fluidically connected with the one or more gassources and are configured to cause gas from the one or more gas sourcesto be provided to the one or more plenum volumes at a rate of between 25and 150 standard liters per minute and the one or more radial gaspassages are sized such that the gas from the one or more plenum volumesflows from the one or more radial gas passages with a velocity of atleast 5 m/s.
 11. The apparatus of claim 1, wherein the first portion ofthe turret has a first nominally circular cross-section and the aperturehas a corresponding second nominally circular cross-section with adiameter larger than the diameter of the first nominally circularcross-section.
 12. The apparatus of claim 1, wherein the one or moreradial gas passages includes only a single gas passage that is in theform of a radial slit that extends around the entire aperture withoutany disruptions in continuity.
 13. The apparatus of claim 1, wherein thefirst gap is between 0.5 mm and 5 mm around the turret.
 14. Theapparatus of claim 1, further comprising a bellows, wherein: a first endof the bellows is fixed relative to an end of the turret located withinthe base, a second end of the bellows opposite the first end is fixedrelative to a surface of the base on an opposite side of the base fromthe aperture, the bellows expands responsive to translation of theturret away from the surface of the base, and the bellows contractsresponsive to translation of the turret towards the surface of the base.15. The apparatus of claim 14, wherein: the bellows has a first averageenclosed cross-sectional area when viewed along the first axis, theoutermost surface or surfaces of the first portion of the turret definea second average cross-sectional area when viewed along the first axis,and the first average enclosed cross-sectional area is substantiallyequal to the second average cross-sectional area.
 16. The apparatus ofclaim 14, wherein: the first portion of the turret is nominally circularand has a first nominal diameter, the bellows has a plurality of pleats,each pleat has an inner diameter and an outer diameter, and the averageof the inner diameters and outer diameters of the pleats issubstantially equal to the first nominal diameter.
 17. The apparatus ofclaim 14, wherein the base has one or more vents in the surface of thebase and within a region encircled by the bellows when viewed along thefirst axis.